JPH04149097A - Barrel type vapor growth device - Google Patents

Abstract

PURPOSE:To improve growth efficiency and the uniformity of crystal films by mounting nozzles for injecting gaseous raw materials to the side face of a chamber which encloses, with nearly a constant spacing, a barrel type susceptor supported with a perpendicular revolving shaft. CONSTITUTION:The barrel type susceptor 1 mounted with plural semiconductor substrates 2 is supported by the perpendicular revolving shaft 6 and the nozzles 4 for injecting the gaseous raw materials via bellows 9 are mounted to plural gas introducing pipes 5 provided on the side face of the chamber 3 which encloses this susceptor 1 with nearly a constant spacing therebetween. The gaseous raw materials supplied from a gas supply source 11 are supplied via gas flow rate controllers 20 provided to each of the nozzles 4, the nozzles 4 and the gas introducing pipes 5 into the chamber 3 to grow the crystal films in a vapor phase on the heated substrates 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a vapor phase growth apparatus for Ⅰ-V group compound semiconductors, etc., having a barrel-shaped susceptor.

[Conventional technology]

FIG. 4 is a sectional view of a conventional barrel type vapor phase growth apparatus.

(For example, Japanese Unexamined Patent Publication No. 1-294598) A plurality of semiconductor substrates 2 are mounted on a susceptor 1 supported by a vertical rotation shaft 6, and source gas is supplied from a nozzle 4 provided at the top of a chamber 3. The raw material gas is supplied in the form of a gas flow 8, and is heated onto the semiconductor substrate 2 by a gas phase reaction or a thermal decomposition reaction on the surface of the semiconductor substrate 2, which is heated to a predetermined temperature by heating means such as high-frequency induction heating or resistance heating. After the crystal film is formed, it is discharged from the exhaust lower part of the chamber 3.

[Problem to be solved by the invention]

The conventional vapor phase growth apparatus as described above has excellent mass productivity because it can process a plurality of semiconductor substrates at the same time. but,
Since the raw material gas passes almost parallel to the surface of the substrate, a large amount of the raw material gas does not contribute to the formation of the crystal film and is emitted as is, resulting in a problem of low growth efficiency, that is, raw material utilization efficiency. Ta.

The present invention aims to eliminate the above-mentioned drawbacks of the conventional apparatus and provide a vapor phase growth apparatus having a barrel-shaped susceptor, which has significantly improved growth efficiency.

[Means to solve the problem]

The present invention includes a barrel-type susceptor on which a semiconductor substrate is mounted, which is supported by a vertical rotating shaft, a chamber surrounding the susceptor at a substantially constant interval, and a nozzle for injecting raw material gas onto the side surface of the chamber. This is a vapor phase growth apparatus characterized in that it takes 0.01 digits. Another feature is that a plurality of gas introduction pipes are provided on the side surface of the chamber radially around the chamber axis, and a nozzle for injecting the raw material is attached to each gas introduction pipe via a bellows.

Furthermore, the present invention is characterized by providing means for independently controlling the flow rate of gas injected from each nozzle.

[Operation] The vapor phase growth apparatus of the present invention is characterized in that a nozzle for injecting source gas is attached to the side surface of the chamber, and the source gas is injected directly toward the vicinity of the substrate surface from this nozzle. Therefore, the supplied raw material gas effectively contributes to film formation, and high growth efficiency can be obtained.

Further, a plurality of gas introduction pipes were provided on the side of the chamber, and a nozzle was attached to each gas introduction pipe via a bellows. Therefore, compared to the case where there is only one nozzle, the gas flow inside the chamber becomes more uniform, the uniformity of the formed crystal film can be improved, and the nozzle can be freely adjusted with respect to the gas introduction pipe. Therefore, it is possible to set the optimum nozzle angle and position from the viewpoint of growth efficiency and uniformity of the crystal film.

Furthermore, as a result of independently controlling the flow rate of gas injected from each installed nozzle, it is possible to supply exactly the same amount of gas from each gas introduction pipe.

[7] Therefore, the flow of the raw material gas to each substrate mounted on the susceptor can be made uniform, and the uniformity of the thickness and impurity concentration of the grown crystal film among each wafer is improved.

Also, if the crystal film is uneven due to slight unevenness in the gap between the susceptor and the chamber, finely adjust the amount of gas supplied from each gas introduction pipe. By doing so, it is also possible to ensure the uniformity of the crystal film.

〔Example〕

FIG. 1 is a schematic cross-sectional view of a barrel-type vapor phase growth apparatus showing an embodiment of the present invention. A plurality of semiconductor substrates 2 can be mounted on a barrel-shaped susceptor 1 supported by a vertical rotation shaft 6. A chamber 3 surrounding the susceptor 1 is provided at a substantially constant interval, and a nozzle 4 is attached to a gas introduction pipe 5 provided on the side surface of the chamber 3 via a bellows 9.

The length of the gas introduction pipe 5 is 300 mm, and the diameter φ is 25 mm.
The sample was taken at an angle of θ1-60° with respect to the chamber 3.

Also, the board mounting surface of susceptor 1 is at an angle θ with respect to the vertical direction.
The inclination was 2-6 degrees, and the distance 1 between the center of the substrate 2 and the inner wall surface of the chamber 3 was 20 mm. Four gas introduction pipes 5 were provided radially around the chamber/<3 at equal intervals.

A GaAs crystal film was grown using the vapor phase growth apparatus of the above example.

The total feed rate of raw material gas was 60 l/min, and this was distributed and fed to each gas introduction pipe. In the raw material gas, the flow rate of trimethyl gallium was 50 m1 per minute, and the flow rate of AsHa was 10 m1 in hydrogen.
% dilution was fed at a flow rate of 81 per minute.

A GaAs substrate 2 with a diameter of 50 mm is heated to 65 mm by resistance heating.
Heated to 0°C.

After growing for one hour under the above conditions, a GaAs crystal film with a thickness of 3.5 μm was obtained at the center of the GaAs substrate 2.

For comparison, the fourth test was conducted under the same gas flow rate and temperature conditions.
Similar growth was performed using the conventional vapor phase growth apparatus shown in the figure. The thickness of the obtained GaAs crystal film was 1μ at the center of the substrate.
It was m.

FIG. 2 shows a comparison of the thicknesses of crystal films grown using the vapor phase growth apparatus of the present invention and those grown using a conventional vapor phase growth apparatus. It was confirmed that when growth was performed under the same flow rate conditions, the device of the present invention could obtain a thickness approximately 3.5 times that of the conventional device. As seen in FIG. 2, the film thickness distribution within the plane of a substrate with a diameter of 50 mm was ±6% or less, which was comparable to that of the conventional device.

In the embodiment described above, the nozzle was attached to the gas supply pipe via a bellows so that its angle and position could be adjusted. However, in applications where a film is always formed under constant conditions, for example, fixing the angle and position of the nozzle simplifies the mechanism and reduces problems such as gas leakage. In such a case, it is desirable to insert the nozzle directly into the chamber at a predetermined angle via the bellows.

The angle at which the raw material gas is blown onto the susceptor 1 was θ1+θ2−66° in the example, but this angle was changed to 30°.
The angle can be selected as appropriate within a range of about 80°. 3
When the angle is smaller than 0°, the gas flow 8 flows almost parallel to the substrate 2, similar to the conventional vapor phase growth apparatus.
Growth efficiency is poor.

On the other hand, if the angle is larger than 80°, the gas flow 8 will flow at an angle close to perpendicular to the substrate 2, and the gas flow passing through the surface 2 of the substrate 2 will likely become non-uniform within the plane, resulting in crystallization. The uniformity of the film is compromised.

Furthermore, as shown in FIG. 3, if the apparatus is configured such that a gas flow rate regulator 10 is provided for each nozzle and the raw material gas supplied from the gas supply source 11 is independently controlled for each nozzle,
Since it is possible to correct the non-uniformity of the gas flow within the chamber due to a slight misalignment between the central axes of the chamber and the susceptor, it is possible to further improve the uniformity of the crystal film.

〔Effect of the invention〕

By adopting the above configuration, the present invention makes it possible to effectively use raw material gas to form a crystal film, and achieves high growth efficiency in a barrel-type vapor phase growth apparatus that processes multiple wafers simultaneously. It has the excellent effect of being able to grow.

Furthermore, a grown crystal film with good uniformity can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a barrel-type vapor phase growth apparatus showing an embodiment of the present invention. FIG. 2 is a graph showing the distribution in the substrate plane of the thickness of crystal films grown using the present invention and the conventional vapor phase growth apparatus. FIG. 3 is a conceptual diagram of a vapor phase growth apparatus showing another embodiment of the present invention. FIG. 4 is a schematic cross-sectional view of a conventional barrel type vapor phase growth apparatus. 1. Susceptor 2. Semiconductor substrate 3. Chamber 4. Nozzle 5. Gas introduction pipe 6. Vertical rotation axis 7. Exhaust port 8. Gas flow 9. ...Verogas flow controller gas supply source

Claims (3)

[Claims] (1) A barrel-shaped susceptor on which a semiconductor substrate is mounted is supported by a vertical rotating shaft, a chamber is provided surrounding the susceptor at a substantially constant interval, and a nozzle for injecting raw material gas is attached to the side of the chamber. A barrel-type vapor phase growth device featuring: (2) Claim (1) characterized in that a plurality of gas introduction pipes are provided on the side surface of the chamber radially around the chamber axis, and a nozzle for injecting the raw material is attached to each gas introduction pipe via a bellows. Barrel type vapor phase growth apparatus described. (3) The barrel type vapor phase growth apparatus according to claim (2), further comprising means for independently controlling the flow rate of the gas injected from each nozzle.